Legal advice on business scam?

I'm a small business owner that seldom place any ad with Yellow Page. Couples of weeks ago, I received a bill from YellowPage-California which has "walking fingers" for the amount of $1,068. I've never come to agreement with this company in any kind, and certainly have no idea where the balance comes from. I tried to contact them but got no single response. It might be that one of my employee mistakenly took them as the official ATT Yellow Page. I don't want to pay for something that I never wanted or ordered. If anyone ever came across this scam, please advise! Legal advice is much appreciated.